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Proceedings Paper

Overlay metrology for low-k1: challenges and solutions
Author(s): Jens Timo Neumann; Jongsu Lee; Kiho Yang; Byounghoon Lee; Taehyeong Lee; Jeongsu Park; Chang-moon Lim; Donggyu Yim; Sungki Park; Eric Janda; Kaustuve Bhattacharyya; Chan-ho Ryu; Young-Hong Min; Kiki Rhe; Bernd Geh
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Paper Abstract

Typical overlay metrology marks like Box-in-Box or Advanced-Imaging-Marks print surprisingly poor when exposed with extreme off-axis-illumination. This paper analyzes the root-cause for this behavior and establishes a method how to understand and predict the results of overlay metrology on resist. A simulation flow is presented which covers the lithographic exposure as well as the actual inspection of the resist profiles. This flow is then used to study the impact of scanner/process imperfections on the overlay measurements; both image-based and diffraction-based overlay metrology are covered. This helps to gain a deeper understanding of the critical parameters in the printing and inspection of overlay marks, and eventually develop and assess mark enhancement strategies for image-based overlay metrology such as chopping, or assess the benefit of diffraction-based overlay metrology. In parallel to the simulations, results of wafer exposures are presented which investigate various aspects of overlay metrology and validate our simulations.

Paper Details

Date Published: 13 March 2012
PDF: 21 pages
Proc. SPIE 8326, Optical Microlithography XXV, 832602 (13 March 2012); doi: 10.1117/12.916376
Show Author Affiliations
Jens Timo Neumann, Carl Zeiss SMT GmbH (Germany)
Jongsu Lee, Hynix Semiconductor Inc. (Korea, Republic of)
Kiho Yang, Hynix Semiconductor Inc. (Korea, Republic of)
Byounghoon Lee, Hynix Semiconductor Inc. (Korea, Republic of)
Taehyeong Lee, Hynix Semiconductor Inc. (Korea, Republic of)
Jeongsu Park, Hynix Semiconductor Inc. (Korea, Republic of)
Chang-moon Lim, Hynix Semiconductor Inc. (Korea, Republic of)
Donggyu Yim, Hynix Semiconductor Inc. (Korea, Republic of)
Sungki Park, Hynix Semiconductor Inc. (Korea, Republic of)
Eric Janda, ASML Netherlands B.V. (Netherlands)
Kaustuve Bhattacharyya, ASML Netherlands B.V. (Netherlands)
Chan-ho Ryu, ASML Korea Co., Ltd. (Korea, Republic of)
Young-Hong Min, ASML Korea Co., Ltd. (Korea, Republic of)
Kiki Rhe, ASML Korea Co., Ltd. (Korea, Republic of)
Bernd Geh, Carl Zeiss SMT Inc./ASML TDC (United States)


Published in SPIE Proceedings Vol. 8326:
Optical Microlithography XXV
Will Conley, Editor(s)

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